Enhanced flux pinning properties of NaNbO3 nanorods added YBCO composite superconductor

Highlights: • No change in the orthorhombic crystal structure of YBCO in all nanocomposite samples. • A decrease in T_c from 92 K to 90.5 K for 2 wt% concentration of NaNbO₃ in nanocomposite sample. • Significant enhancement in critical current density and pinning force of the order of ~2.5 times for 0.5 wt% added composite sample in comparison to pure YBCO. -- Abstract: In this work, sodium niobate (NaNbO₃) nanorods (NR) – YBCO superconductor composites with different wt% (0–2%) of NaNbO₃ were prepared via a two-step process of hydrothermal and solid-state reaction, and its structural, electrical, and magnetic characterizations were carried out. XRD studies revealed that the orthorhombicity of YBCO is preserved in all nanocomposite samples. The superconducting transition temperature decreases from 92 K to 90.5 K when the addition of NaNbO₃ was increased to 2 wt%. Magnetization studies revealed a significant increase of critical current (J_c) and pinning force (F_p) in the NaNbO₃ (NR) added YBCO sample which has been attributed to the creation of artificial pinning centers due to the presence of NaNbO₃ NR. For the 0.5 wt% nanorods added sample, the enhancement in J_c and F_p was maximum. Temperature and field dependence of J_c were carried out to probe the nature of pinning in the nanocomposite superconductors.